The availability of inexpensive audio input sensors (e.g., microphones) has dramatically increased the use of teleconferencing for both business and personal multi-party communication. By allowing individuals to effectively communicate between physically distant locations, teleconferencing can significantly reduce travel time and/or costs which can result in increased productivity and profitability.
With increased frequency, teleconferencing participants can connect devices such as laptops, personal digital assistants and the like with microphones (e.g., embedded) over a network to form an ad hoc microphone array which allows for multi-channel processing of microphone signals. Ad hoc microphone arrays differ from centralized microphone arrays in several aspects. First, the inter-microphone spacing is generally large which can lead to spatial aliasing. Additionally, since the various microphones are generally not connected to the same clock, network synchronization is necessary. Finally, each speaker is usually closer to the speaker's microphone than to the microphone of other participants which can result in a high input signal-to-interference ratio.
Conventional teleconferencing systems have proven frustrating for teleconferencing participants. For example, overlapped speech from multiple remote participants can result in poor intelligibility to a local listener. Overlapped speech can further cause difficulties for sound source localization as well as beam forming.